In the fast growing consumer electronic product market, there is increasing competition not only in product functionality but also in product reliability performance. For hand held electronic gadgets, the impact proof requirement is becoming more and more stringent. It is not unusual now to require a hand held device like a mobile phone to survive the impact from a 5000 gram weight and/or a free drop from a height of 1.5 meters to a steel plate, a process that can be repeated up to 10 times during a test.
Another electronic device that is also tested under similar conditions, a backplateless silicon microphone, was previously disclosed in a Silicon Matrix Pte Ltd patent application S106-002 and features a movable diaphragm which is supported at its edges, corners, or center by mechanical springs that are anchored to a conductive substrate through rigid pads. In addition, there are stoppers formed above perforated plate extensions of the diaphragm that restrict large movements in a direction perpendicular to an underlying backside hole and thereby minimize breakage. However, the stopper components complicate the fabrication process and there may be a compatibility issue between the stopper and the silicon membrane to which it is attached. Therefore, an improved silicon microphone design is desirable that features a structure to prevent device breakage from strong impact and can be made by a method that does not add complexity to the fabrication process or result in compatibility issues between various components.